You never know what might have happened, had he stayed, he might have slumped and they don't win at all, or he could have sustained a career ending injury or got killed in a traffic accident driving to the ballpark.
You can't go back in time and say what would have happened if....
Kind of the one butterfly thing with time travel, or various versions of it like portrayed on " Back to the Future ", " Star Trek ", etc.
If I were some superstar ballplayer, probably married with children, I'd look out for my family interests first, 300 M vs. 250 M, makes no difference ! You gonna drive a better car or have a better house or something with 50 M more ?
It's all ego if you just want the biggest contract for your position.
If my family is best suited to be in the Pacific Northwest, then there are 3 teams up there, if Florida fits, a couple of options there and Atlanta, if the Northeast is your bag, 4 options there, why go to some place like Kc, Detroit,or Denver just for more money you don't need, if Tampa or Seattle is perfect ?